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Tristan T

Help with propane forge

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I recently followed one of those coffee can forge videos utilizing pop and sand. I am aware that this is a heat sink, but have already put a lot of work into the forge and want to finish it regardless if it is inefficient. My main problem is after running for 20 seconds the propane torch appear to run out of oxygen and sputter out. The problem isn't the propane as I have run it by itself and it hasn't gone out. Any help or feedback would be appreciated. Please let me know if you need pictures.

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Sounds like you need a little more of a gap around the torch head so it can suck more air in, or there is too much back pressure so you need more opening out the door of the forge.  

 

Also, the larger problem with the PoP and sand is that it isn't a refractory at all.  Meaning it does not hold up to forging temperatures.  It will start to crumble pretty quickly.  Proper refractory materials are a little more expensive, but they last MUCH longer, and in that regard they are pretty cheap.  

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Yep.  You can get 1" #8 inswool for $10/foot here: https://www.hightemptools.com/inswool.html

That's enough to line two  coffee can forges and will last a very long time, especially if you give it a topcoat of another real refractory.  That same site sells a 1lb bag of Satanite for $4.50.  That's enough to line two coffee can forges and have a good bit left over.

Last time I priced a carton of plaster and a bag of sand at the big box store it came out a little more expensive than using the right stuff in the first place.  When your mix falls out after the third or fourth time you run it, replace it with the real stuff. 

Oh, and where is your burner tip relative to the forge body?  These like to run with the tip just outside the shell.  If you put it all the way in is gets starved for air like Jerrod said.

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2 hours ago, Jerrod Miller said:

Sounds like you need a little more of a gap around the torch head so it can suck more air in, or there is too much back pressure so you need more opening out the door of the forge.  

 

Also, the larger problem with the PoP and sand is that it isn't a refractory at all.  Meaning it does not hold up to forging temperatures.  It will start to crumble pretty quickly.  Proper refractory materials are a little more expensive, but they last MUCH longer, and in that regard they are pretty cheap.  

Thanks! i was already half way done with the forge when i learned about the plaster of paris problem. Hoping to heat treat one knife with this forge and then upgrade it to a firebrick kaowool situation

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You are having the torch come in the side of the can, yes?  Then presumably you have a drill to make the initial hole.  Therefore, just use a slightly bigger drill bit to expand the current hole.  The PoP and sand mix won't be great for the drill bit, but not that bad either.  Light pressure should keep the plaster from cracking, but again, not a huge loss if it does.  

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2 hours ago, Tristan T said:

Also, any suggestions on how to enlarge the size of the hole which the propane goes through?

 

It's not entirely clear what you mean here. Do you mean the size of the hole through your "refractory" and into which you stick the torch, or the size of the gas jet in the torch?

 

I once made a 2-brick forge and tapered the hole for the torch to go in. By moving the torch in and out of the tapered hole (wider at the outside), it was possible to vary the amount of air that was drawn in and thereby vary the temperature. (tip: in most cases, more air = hotter)

 

The problem with using a torch, which is designed to work in open air and draw secondary air, is that it usually can't get enough secondary air to burn with the gas when used in a forge. If you open out the gas jet, you will almost certainly make things worse: even more gas and no more air producing an even richer burn and lower temperature.

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Check out the Build a Gas Forge and the Ribbon Burner attachments on the Forge Supplies page at www.WayneCoeArtistBlacksmith.com.

Let me know if I can help you.

 BTW, I sell the 8#  Inswool for $9.00 per foot and Kast-0-Lite for the castable refractory.  This is a light weight insolating castable.  You should over coat the casting with Metrikote.

 

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On 11/18/2019 at 7:14 PM, Wayne Coe said:

Check out the Build a Gas Forge and the Ribbon Burner attachments on the Forge Supplies page at www.WayneCoeArtistBlacksmith.com.

Let me know if I can help you.

 BTW, I sell the 8#  Inswool for $9.00 per foot and Kast-0-Lite for the castable refractory.  This is a light weight insolatingcastable.  You should over coat the casting with Metrikote.

 

How much is shipping?

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Tristan, S&H depends on what you are ordering.  Send me an e-mail with your details and I will get right back to you.

 

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